To capture a modem trace, you must configure your application to enable trace output over Universal Asynchronous Receiver/Transmitter (UART). You can do this by adding the nrf91-modem-trace-uart snippet to your application's build configuration, as described in the nRF Connect SDK documentation.
Note
By default, the nRF Connect SDK's modem library uses the UART1 peripheral for trace output. This means that you cannot use UART1 for other purposes in your application. If this does not work for your application, you must update the configuration and code of the modem library to use a different UART peripheral for trace output.
Note
In the nRF Connect SDK versions earlier than v2.5.0, it was necessary to manually set the CONFIG_NRF_MODEM_LIB_TRACE Kconfig option in the application instead of using the snippet.
- In the nRF Connect SDK versions v1.5.0 - v2.0.0, the option was called
CONFIG_NRF_MODEM_LIB_TRACE_ENABLED. - In the nRF Connect SDK v1.5.x, setting the option temporarily might cause a build error. In that case, set the option permanently in the
prj.conffile. - In the nRF Connect SDK versions before v1.5.0, the option was called
CONFIG_BSD_LIBRARY_TRACE_ENABLED.
See Configuring Kconfig for instructions on how to set this option temporarily or permanently.